AUGUSTA – An intentionally set fire heavily damaged a two-unit apartment building along a busy street north of the State House early Tuesday.

The two residents of the second-floor unit got out of the State Street building in time and were not injured. The first-floor apartment was not occupied.

The Augusta Fire Department said the alarm came in at about 2:10 a.m. A Chelsea firefighter hurt his hand and an Augusta firefighter hurt his shoulder while the fire was being put out.

Sgt. Ken Grimes of the State Fire Marshal’s Office said the fire was set intentionally near the first-floor rear porch. The fire caused extensive damage to the exterior and roof.